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History of Genetics Research Timeline
Transcript of History of Genetics Research Timeline
Timeline What: They performed a number of experiments that helped confirm that DNA is the molecule of genetic material
How: Bacterial viruses (phages) consisted of a DNA molecule surrounded by a protein coat and when it infects a bacteria, that attach to the surface of the bacterium and inject the DNA into the cell and the protein coat remains on the outside of the cell.
This demonstrated that the DNA, not the protein, carries the genetic information.
Why: Once the DNA was inserted, it did not remain in the cytoplasm of the bacterial cell but was incorporated into the bacteria
Influence of Society: In the 1950's, biologists still believed that proteins carried genetic information and with the Avery-Macleod-McCarty findings, Hershey and Chase set out to prove their discovery.
Awards/Works: Nobel Prize in Physiology or Medicine (1969) What: Discovered that variations among species were caused by natural selection and proposed the Theory of Natural Selection which helped lay the foundation of the Theory of Evolution
Why: Darwin's exposure to specimens all over the globe intrigued him and raised important questions to him, like their origins and their connections to other species who shared similar characteristics
How: Darwin traveled to a secluded island called Galapagos and studied the variations between species and the environment in which they lived in. By studying these animals, particularly finches, he found that the species have evolved according to the food their environment supports. For example, Darwin discovered that the different variations of the finch's beak is due to the food they eat, in which their beak eventually diversified and evolved to accommodate their diet
Influence of Society: Explorations were being taken to the New World to discover new places and answers and Darwin took this opportunity to undergo his own exploration to the Galapagos islands to answer his own questions about the history of species.
Awards/ Work : He worked on his theory for 20 years and published "On the Origin of Species by Means of Natural Selection" in 1859 that became a very controversial book towards Creationism. Awards/Work: Basic Laws of Heredity, published a short monograph called "Experiments with Plant Hybrids" Stevens observing meal worms and their chromosomes What: Found that the males made reproductive cells with boy X and Y chromosomes whereas the females made only those with X. She concluded that sex is inherited as a chromosomal factor and that males determine the gender of the offspring
How: She looked at sex determination in the mealworm. While investigating the mealworms, she found female cells contained 20 chromosomes, but male cells contained 19 large chromosomes and one very small one. She showed that the X body paired with the 20th, much smaller, chromosome in meiosis. She proposed that these two chromosomes be called X and Y, and explained that females contained two X chromosomes
Why: She was interested in the process of sex determination
Influence of society: Her passion for education and her determination to not follow normal occupations for women encouraged Stevens to continue her college education and eventually pursue a career in genetics
Awards/ Work: Chromosomal Theory of Inheritance, Ellen Richards Research Prize (1905) What: Showed how genes direct the synthesis of enzymes that control metabolic processes and used Neurospora to prove that "one gene makes one protein."
How: They mutated Neurospora which produced some organisms with mutant genes that were then crossed with non-irradiated Neurospora. Although in normal situations the sexual recombination of the organism could still multiply in a single growth medium, Beadle and Tatum showed that some mutant spores " would not replicate without addition of a specific amino acid-arginine." They then produced four strains of arginine-dependent Neurospora which all have lost use of a specific gene that facilitates an enzyme that is used for the production of arginine.
Why: They wanted to develop an experiment that would demonstrate a link between genes and their chemical products and Neurospora proved to be an ideal product to test because any mutation that occurred would be immediately expressed
Influence of Society: Beadle was influenced by a teacher who encouraged him to follow science and persuaded him to go to the College of Agriculture, Tatum was influenced by his father who was a Professor of Pharmacology and his interest in nutrition and metabolism of bacteria
Awards/Work:Nobel Prize in Physiology or Medicine in 1958, Beadle won the 1950 Albert Lasker Award for Basic Medical Research, Tatum received the Remsen Award of the American Chemical Society in 1953 1944 1950 Chargaff found that the chemical structures of DNA pair up in a particular way ( adenine with thymine and cytosine with guanine) 1951 x-ray diffraction of DNA Hershey and Chase Experiment Main Contribution:clarified the structure of the smallest units of matter, constructed the first satisfactory model of a protein molecule Main Contribution:Solved the three-dimensional structure of the DNA molecule. The bacteria E.Coli Thomas Morgan What: Produced the first recombinant DNA molecules
How: Inserted DNA from one species into a molecule, opening the way to modern genetic engineering, used his technique to study viral chromosomes
Why: When the genetic material from one organism was introduced to the genome of another organism, the genetic material was replicated and expressed by that other organism
Influence of Society: A greater attention to molecular and medical biology
Awards/Works: Nobel Prize in Chemistry (1980) Dideoxy Method 1989 Main Contribution: Identified the gene coding for the cystic fibrosis transmembrane conductance regulator protein (CFTR) on chromosome 7 that, when mutant, causes cystic fibrosis. 1995 J. Craig Venter What:discovered the first TypeII restriction enzyme (HindII) and determined the sequence of its cleavage site (The site in a polynucleotide chain as to where the restriction enzyme cleaves nucleotides by hydrolyzing the phosphodiester bond between them)
How: He used the same approach that Danna & Nathans used with the eukaryotic virus SV40. They used the enzyme to cut the DNA of the eukaryotic virus SV40 into 11 fragments and separated the fragments using gel electrophoresisas, a way to sort nucleic acid molecules of different sizes.
Why: He used this technique because it was being demonstrated at Johns Hopkins and saw it as a successful way to approach his enzyme
Influence of Society: While employing himself in the Navy ( Being a part of the Doctor's Draft), he felt too relaxed and idle and began to search for an interest and found a new research on human chromosomal aberrations.
Awards/ Work: Nobel Prize in Physiology or Medicine (1978) The Fruit Flies that Morgan bred Main Contribution: Proposed a theory of sex-linked inheritance for the first mutation discovered in the fruit fly, Drosophila, white eye. This was followed by the gene theory, including the principle of linkage. 1910 What: He studied mutation with fruit flies and demonstrated that genes are carried on chromosomes and are "mechanical basis of heredity." His discoveries formed the basis of the modern science of genetics.
How: While he began to breed fruit flies, a number of mutations turned up. Morgan looked for the location of these mutations and succeeded, demonstrating that the associations known as coupling and repulsion were "the obverse and reverse of the same phenomenon known as linkage"
Why: He was introduced to breeding by F.E.Lutz who got Morgan interested in the effects of inbreeding
Influence of society: Natural history and his interest in collecting birds, eggs and fossils encouraged him to work at Alphaeus Hyatt (a laboratory) and United States Fish Commission at Woods Hole
Awards/Works: Wrote "Heredity and Sex" (1913), "The Physical Basis of Heredity (1919) and many more works, Awarded the Nobel Peace Prize in 1933, made a Foreign Member of the Royal Society of London (1919), awarded the Darwin Medal in 1924, and the Copley Medal of the Society in 1939 Frederick Griffith Streptococcus Pneumoniae 1928 What: Discovered Streptococcus Pneumoniae could be made lethal after exposing it to heat-killed virulent strains.
How: Griffith's experiment involved mice and two types of pneumonia, a virulent and a non-virulent kind. He injected the virulent pneumonia into a mouse and the mouse died. Next he injected the non-virulent pneumonia into a mouse and the mouse continued to live. After this, he heated up the virulent disease to kill it and then injected it into a mouse. The mouse lived on. Last he injected non-virulent pneumonia and virulent pneumonia, that had been heated and killed, into a mouse. This mouse died. This observation led him to believe that some "transforming principle" from the heat-killed virulent strain converted the non-virulent strain in to the virulent strain.
Why: He was working on a project that enabled others to point out that DNA was the molecule of inheritance
Influence of Society: During WWI, he became part of the Ministry of Health's Pathological Laboratory where he was a medical officer
Awards/ Works: none George Beadle & Edward Tatum Main Contribution: Irradiated the red bread mold, Neurospora, and proved that the gene produces its effect by regulating particular enzymes. 1941 The Neurospora that Beadle and Tatum worked with 1952 Hershey and Chase Pauling's Protein Model Main Contribution: Used phages in which the protein was labeled with 35S and the DNA with 32P for the final proof that DNA is the molecule of heredity. 1951 What: He worked to understand the properties of chemical substances and their structure, and in doing so, he was able to clarify the smallest units of matter; he also constructed a model of a protein and studied abnormal and normal structures of the protein and its effects, and also created a synthetic antibody
How: He determined the structure of inorganic compounds and then tried to understand the rules that made up the structures of the molecules, predicting the chemical/physical properties of the atoms and ions; For his protein model he began with proteins and amino acids which he called the "building blocks of life" and studied their behavior and characteristics
Why: He worked in the quantum mechanics/theoretical chemistry field at Cal Tech, His interest in the behavior of these molecules also led him to biological chemistry, becoming interested in their functioning and "architecture"
Influence of Society: He was always interested in chemistry and did experiments of his own at an early age and decided to pursue it, The atomic bomb near the end of the war also interested Pauling into studying the effects of nuclear exposure on the molecular structures
Awards/Works: Nobel Prize in Chemistry (1954), Peace Prize (1962), Presidential Medal of Merit (1948) Linus Pauling What: She used x-ray diffraction techniques with DNA to study its structure like their fibers reactions to humid conditions
How: By using the x-ray diffraction technique and adjusting it to produce an extremely fine beam of x-rays, she extracted finer DNA fibers and arranged them in parallel bundles, studying their reactions to humid conditions. This allowed her to discover crucial keys to DNA's structure
Why: She was assigned to work on DNA at the King's College with Maurice Wilkins
Influence of Society: Due to the war breakout, she stayed in Cambridge, continuing her education that would eventually lead her to King's College where she would work on DNA, discovering its structure and properties
Award/Work: Published a proposed structure of DNA in 1953, Main Contribution: Obtained sharp X-ray diffraction photographs of DNA. Rosalind Franklin What: Showed that DNA, not amino acids, in the cell carries the genetic information and also found the chemical structures that make up DNA
How: He determined the composition of DNA through paper chromatography and ultraviolet spectroscopy that led to the correct molecular structure and his findings became known as Chargaff's Rules...
1. the number of adenine (A) residues always equals the number of thymine (T) residues;
2. the number of guanine (G) residues always equals the number of cytosine (C) residues;
3. the number of purines (A+G) always equals the number of pyrimidines (T+C) — this rule is an obvious consequence of rules 1 and 2.
these findings compared with Franklin's X-ray studies of DNA suggested that pairing existed between adenine and thymine, and betweem guanine and cytosine
Why: While he studied lipid metabolism and blood coagulation, he began to concentrate on the DNA molecule and, following Avery's discovery, he thought that there must be more different types of DNA molecules than people had believed
Influence of Society: Chargaff's global education ( due to WWII) , studying in Vienna, America, and Paris, opened him up to a range of biomedical fields that would eventually lead him to studying DNA
Awards/Works: National Medal of Science for Biological Sciences (1974) and the Pasteur Medal (1949) Main Contribution:Discovered the key facts necessary to determine the basic chemical structure of DNA (adenine, guanine, thymine, and cytosine) Erwin Chargaff Main Contribution:Reported that they had purified the transforming principle in Griffith's experiment and that it was DNA. Maclyn
Macleod What: Showed that DNA is the "transforming material" in cells and is the chemical basis for specific and heritable transformations in bacteria
How: The transformation of Streptococcus Pneumoniae from a non virulent type to a virulent type is due to transferring DNA from a dead, smooth organism to live rough ones. This also showed that the transforming principle is destroyed by an enzyme that hydrolyzes DNA.
Why: They were baffled by the bacteria that causes pneumonia and wondered what made the transformation- turning a non deadly R bacteria to a lethal bacteria when it combines with a lethal S form.
Influence of Society: It became popular at the Rockefeller Inst. for Medical Research to find the "transforming principle" of Griffith's experiment of 1928 and later influenced Avery, McCarty, and Macleod to join the other scientists in search for the answer
Awards/Work: Published a paper in the "Journal of Experimental Medicine" Oswald
Avery Their experiment with mice and the Streptococcus Penumoniae strains Meselson-Stahl experiment overview 1958 Main Contribution: Used isotopes of nitrogen to prove the semi-conservative replication of DNA. Meselson and Stahl 1970 Hamilton Smith 1983 Nancy Wexler What: First to connect a human disorder with Mendel's laws of inheritance and proposed the idea that diseases came about "through metabolic route leading to the molecular basis of inheritance", or "inborn errors of metabolism." He also concluded that normal variations and abnormal variations in ones chemical makeup are determined by genetics
How: He was studying Alkaptonuria (a human disorder) and while collecting family history from his patients, he found that Alkaptonuria is a recessive disorder ( a pattern of inheritance described by Mendel's experiments with peas)
Why: He became interested in science especially biochemistry and genetics. He began to suspect that, due to a genetic defect, patients with Alkaptonuria lacked an enzyme involved in the chemical breakdown of protein (aka metabolism)
Influence of society: His teachers recognized and encouraged him to go into the field of science and medicine at Oxford University and he was also influenced by his father who was also a physician.
Awards/ Work: Published "The Incidence of Alkaptonuria: a Study in Chemical Individuality" in 1902, and in 1923, published "Inborn Errors of Metabolism", delivered lectures before the
Royal College of Physician in 1908, made fellow of the Royal Society in 1910 1908 Archibald Garrod Nirenberg working with synthetic mRNA Main Contribution: Led teams that cracked the genetic code- that triplet mRNA codons specify each of the twenty amino acids. Nirenberg What: Discovered that mRNA is required for protein synthesis and that synthetic mRNA preparations can be used to decipher the genetic code
How: He studied that steps that relate DNA,RNA, and protein by producing RNA from uracil and then adding a synthetic poly-uracil RNA in a "cell-free extract of Escherichia Coli which contains DNA, RNA, ribosomes and protein." Then they added DNase so that no additional proteins would be produced and then added 1 radioactive amino acid with 19 unlabeled amino acids. The radioactive amino acid resulted in a radioactive protein, proving that mRNA codes for proteins
Why: The radioactive amino acid produced a radioactive protein
Influence of Society: He was always influenced by biology and chemistry since an early age, his interest grew as he became older
Awards/Works: Nobel Prize in Physiology or Medicine (1968), Franklin Medal (1968) 1966 Kornberg What: Was the first to identify DNA in the intestinal bacterium E.Coli, establishing that this enzyme catalyzes the production of new DNA strands. He also showed how a single strand of DNA forms new strands of nucleotides, and proved the double helix structure of DNA
How: He found that DNA polymerase was essential in DNA replication, repair, and rearrangements. These enzymes became the basis of recombinant DNA
Why: He studied mechanisms of the enzymatic synthesis of coenzymes and inorganic pyrophosphate and extended his interest to the biosynthesis of the nucleic acids especially DNA
Influence of Society: He had an internship as a Navy Ship's doctor and continued to study medicine after the Navy at multiple colleges
Awards/Work: Nobel Prize in Physiology or Medicine (1959), Paul-Lewis Award in Enzyme Chemistry (1951), National Medal of Science (1979) 1958 Main Contribution: Purified DNA polymerase I from E. coli, the first enzyme that made DNA in a test tube. What: Discovered the DNA structure was a double helix made up of two chains of nucleotides, one going up and one going down, and that the base pairs interlocked in the middle of the double helix to hold the structure and keep the two chains apart
How: By taking Franklin's helix idea and pairing it with Chargaff's base pair finding, Crick and Watson were able to piece together the DNA structure
Why: Franklin found that her X-ray diffractions showed that the wet form of DNA had characteristics of a helix, and Chargaff's base pairs fit the need for a glue to hold the chains together.
Influence of Society: The recent discoveries and talk about the DNA molecule triggered a race to construct the structure of DNA
Awards/Work: 1962, Nobel Prize for physiology/medicine 1953 Crick and Watson mini satellites Main Contribution: Coined the term DNA fingerprinting and was the first to use DNA polymorphisms in paternity, immigration, and murder cases. Alec Jeffreys What: Developed techniques for DNA fingerprinting and DNA profiling which are now used all over the world in forensic science
How: While trying to isolate mini satellites (sections of human DNA) by using chemical probes to detect certain chemicals that characterized these DNA sections and taking x-ray films of the DNA, he noticed that not only could he see mini satellites but also saw that it varied greatly among people. This uniqueness meant that these mini satellites could be used as a means to identify someone.
Why: The mini satellite's patterns can be examined through the x-ray films, and since they varied for each individual, it meant that each individual could be identified by their mini satellite
Influence of Society: His discovery influenced the forensics field and lawyers who because it could help determine a persons identity, and therefore their background, citizenship, and location
Awards/Works: Fellow of the Royal Society in 1986,987 Davy Medal from the Royal Society, and the 1998 Australia Prize, knighted in 1994, member Academia Europea and of the American Academy of Forensic Sciences. Francis. S Collins CFTR 1989 What: He used positional cloning to find the gene responsible for cystic fibrosis. He also found genes responsible for Huntington's disease, neurofibromatosis, multiple endocrine neoplasia type 1, and the M4 type of adult acute leukemia.
How: They found an abnormality in a gene that looked like its role was transporting ions through cell membranes, a process that goes wrong in those with cystic fibrosis
Why: people with cystic fibrosis lack three base pairs from both copies of this gene, unlike those who do not have cystic fibrosis whose genes always have at least one copy intact. This abnormality causes the protein (produced by this gene) to lack an amino acid called phenylalanine
Influence of Society: The massive heat wave in New York City led to the awareness that more children who came to the hospital during the heat wave had cystic fibrosis because the disease causes children to become dehydrated faster
Awards/ Works: Leader of NHGRI, Collins received the Presidential Medal of Freedom (2007), Kilby International Awards (1993), National Medal of Science (2008) Berg and Boyer Recombinant DNA 1972 Main Contribution: Produced the first recombinant DNA molecules. Sanger Main Contribution:Developed the chain termination (dideoxy) method for sequencing DNA. 1977 What: Solved the problem of DNA sequencing while working on protein sequencing. His method led to the dideoxy method which is now a common method for sequencing reactions
How: The process requires a single strand DNA template, a DNA primer, a DNA polymerase, and modified nucleotides that terminate DNA strand elongation. The sample is divided into four separate sequencing reactions and four dideoxynucleotides are added to each reaction while undergoing rounds of template DNA extension from the bound primer. The result are DNA fragments that are then heat denatured and separated by size. The DNA bands are not able to be visualized by autoradiography/UV light and the DNA sequence can be read off the x-ray film/gel image
Why: To simplify DNA sequencing by using dark bands that indicate a DNA fragment (which is used to read the DNA sequencing)
Influence of Society: He was influenced by his father who was a medical practitioner and by the works of his colleagues like Neuberger and Chibnall.
Awards/Works: Nobel Prize for Chemistry (1958), Nobel Prize in Chemistry (1980) Charles Darwin Main Contribution:
Proposed the Theory of Natural Selection- the members of a population who are better adapted to the environment survive and pass on their traits 1858-1859 Main Contribution:
Published the results of his investigations of the inheritance of "factors" in pea plants Results of Mendel's cross-breeding experiment with pea plants Mendel 1866 What: Proposed theories of heredity based on his work with pea plants and described how traits were inherited. He was the first person to trace the characteristics of successive generations of a living thing. He came up with the basic laws of heredity:hereditary factors do not combine, but are passed intact; each member of the parental generation transmits only half of its hereditary factors to each offspring; and different offspring of the same parents receive different sets of hereditary factors. What: Provided evidence for semi-conservative replication of of the DNA molecule where two parent strands are the template for synthesis of the news strands
How: Bacterial cells are grown for several generations on a medium containing heavy isotope of nitrogen. Their DNA contains heavy nitrogen. The cells are then transferred to a new medium containing the normal lighter isotope. The DNA is then extracted and dissolved in a solution of cesium chloride. After the samples are spun rapidly, the cesium chloride establishes a concentration gradient in the tube. The heavy DNA sinks to a lower position in the cesium gradient. After one generation in the light solution, the bacteria yielded a single band of DNA with a density between that of the light and heavy solution, indicating only one strand of each duplex contained the heavy 15N. After two generations in the same solution, the two bands were obtained, one of intermediate density and one of low density. This concluded that replication of DNA duplex involves building new molecules by separating parent strands and then adding nucleotides to form the complementary strand.
Why: The results showed that the DNA molecules are not "degraded" and "reformed" from free nucleotides between cell divisions, but rather, each strand remains intact as it builds a complementary strand from the nucleotides available.
Influence of Society: Watson and Cricks discovery influenced Stahl and Meselson to explore DNA and its strandsnew
Awards/Works: Their work was published in 1958, Nettie Stevens 1905 Sutton studied grasshopper cells that led him to his discovery Main Contribution: First to provide proof that chromosomes contained the cell's units of inheritance Sutton What: He became the first scientist to provide evidence that chromosomes carried the cell's units of inheritance, genes
How: He studied grasshopper cells and observed that the chromosomes occurred in distinct pairs, and that during meiosis, the chromosome pairs split, and each chromosome goes to its own cell.
Why: He was working at Columbia University as a graduate student, and came across his findings while studying these grasshopper cells
Influence of Society: He was influenced by Mendel's work with heredity and expanded upon his work
Awards/Work: He published a paper called " On the Morphology of the Chromosome Group in Brachyotola" in 1902 to announce his discovery, laid the basis for the Chromosomal Theory of Heredity 1902-1903 By Ellie Wand Different variations of finches that Darwin studied (The different variations correlated with the finches diet and surrounding environment, supporting his theory of natural selection. ) Influence of Society: He attended a school in which natural sciences were emphasized and students learned beekeeping and how to grow fruit which became Mendel's interest and continued to follow him into adulthood How: He planted atypical ornamental plants next to a typical variety and grew their progeny next to each other to see if there would be their traits would be passed on to the next generation. He found that the offspring retained the traits of the parents, concluding that environment was not an influencing factor. After this experiment, he continued to cross breed pea plants and mice of different varieties and saw the traits were inherited in certain numerical ratios. This lead to the idea of dominant and recessive genes. His study of these traits took 7 years with pea plants, and he came up with basic laws of heredity Why: He was attracted to nature, interested in plants and the theories of evolution. He wondered how plants obtained atypical characteristics and began to study atypical variety through ornamental plants. "Father of Genetics" Main Contribution:
Independently described the behavior of sex chromosomes-XX determines female; XY determines male. Main Contribution: Proposed that some human diseases are due to "inborn errors of metabolism" that result from the lack of a specific enzyme. Sample of Alkaptonuria Main Contribution: Proposed that some unknown "principle" had transformed the harmless R strain of Diplococcus to the virulent S strain. DNA double helix Main Contribution: first to sequence the human genome and for creating the first cell with a synthetic genome What: Decoded the genome of the first free-living organism, the bacterium Haemophilus influenzae, using his shotgun technique
How: The shotgun technique- DNA is divided, randomly, into small segments and then sequenced using the chain termination method. After several rounds of multiple reads for the target DNA, using fragmentation and sequencing, Computer programs assemble the overlapping and different reads into a continuous sequence
Why: Although this process is more complex, it allows longer strands of DNA to be coded in a faster time
Influence of Society: He was introduced to medicine while serving in the Navy during the Vietnam War at the Da Nang Hospital
Awards/Works: Published Human Genome (2001), (2008) United States National Medal of Science, (2002) Gairdner Foundation International Award, and in 2001, the Paul Ehrlich and Ludwig Darmstaedter Prize and the King Faisal International Award for Science Shotgun Sequencing Hind II Enzyme Main Contribution: Isolated the first restriction enzyme, HindII, that could cut DNA molecules within specific recognition sites. What: Found the location of Huntington's disease which is located on chromosome 4
How: She tracked polymorphisms as markers (Polymorphism - existence of a species in several forms independent of the variation of sex, existence of a gene in several allelic forms, existence of a molecule as an enzyme in several forms in a single species.) and gave Gusella samples of blood that she had collected from people in Venezuela
Why: The disease is a trinucleotide repeat disorder which are caused by the length of a repeated section of a gene exceeding a normal range, and by tracking the diease using polymorphisms, they were able to find a location
Influence of Society: Her mother had Huntingtons disease and her father studied the disease and founded the Hereditary Disease Foundation
Awards/Works: Albert Lasker Public Service Award in 1993. Main Contribution: Used blood samples collected by Nancy Wexler and her co-workers to demonstrate that the Huntington's disease gene is on chromosome 4. Huntington's Disease 1986 Leroy hood Main Contribution: Developed the automated sequencer What: improved the Sanger method of enzymatic sequencing, making it automatic
How: He automated the process by replacing the use of radioactive labels with fluorescent dyes whose colors corresponded with each of the four DNA bases. This was called "color coding". Hood then used laser and computer technology which eliminated the process of gathering information by hand. As the fragments of DNA filtered through the gel, a laser beam stimulated the fluorescent labels, and the light they emitted was picked up by a lens that transmitted information directly into a computer.
Why: The automatic sequencer allowed more DNA to be sequenced in a faster time, allowing the Human Genome to be coded quicker
Influence of Society: The Sanger Method was too labor intensive and costly, so Hood sought out a faster and cheaper way to sequence genes
Awards/Works: 1987 Albert Lasker Award for Basic Medical Research Automated Sequencer 1996 More than 600 scientists all over the world contributed Main Contribution: Finished sequencing the entire genome of baker’s yeast, an organism that carries versions of many human genes. What: Researchers all over split up the regions of the 16 yeast chromosomes, eventually sequencing its entire genome
How: The yeast's chromosomes were divided among scientists of different countries who put together its sequenced genome, using the automated sequencer
Why: They believed that the yeast genome would help interpret the human genome sequence
Influence of Society: Yeast was already commonly being used in laboratories to investigate basic questions in biology
Awards/ Works: Reported their results in "Science" Baker's Yeast 1998 Sydney Brenner, John E. Sulston, and H. Robert Horvitz Main Contribution: the first multicellular organism, the C. Elegans worm, to have its genome sequenced What: The C.Elegans worm is the first organism to have its entire genome sequenced
How: Since the worm is transparent, these scientists were allowed to track it's gene development from birth to when it became an adult, sequencing its genome one step at a time
Why: Some of our genes show similarities with the worm's genes ( similar to about 40% of ours) and its anatomy, even showing a primitive digestive and neuromuscular system. By decoding its genome, it gives us insight into how genomes of complex organisms function
Influence of Society: For many years scientists have wanted to make the switch from sequencing genomes of nonliving substances to sequencing genomes of organisms and the C.elegan worm seemed to fit the most ideal subject to sequence, with its transparent look and and similar genome to ours.
Awards/Works: 2002 Nobel Prize in Physiology or Medicine The C. Elegan Worm 1999-2000 The Drosophilia Genome A comprehensive article about the Drosophilia Genome that was published in "Science" in 2000 Main Contribution: The Fruit Fly's genome was entirely sequenced and assembled in 1999 and published in 2000 What: A team of scientists completely sequenced the Fruit Fly's genome and published it. Its genome has proven to be helpful, becoming a model organism for geneticists who breed and crossbreed the fruit fly extensively
How: It was assembled by Celera Genomics and funded by the Berkeley Drosophila Genome Project who worked to uncover the genome of the fruit fly and did so in about 8 months. Celera Genomics did the sequencing using a whole-genome shotgun strategy and a extensive clone-based sequence, while BDGP closed the gaps using its database to annotate the genome and produce a physical map of it
Why: The fly's chemistry and genetic counterparts to human diseases (including cancer) made it interesting and useful to decode and explore its genome
Influence of Society: The technological (shot-gun sequencing method) and genetic advancements ( like the chromosome theory of heredity)with the fruit fly's well known rapid breeding habits and familiar characteristics, made the sequencing of its genome interesting and potentially useful
Awards/ Works: Published its genome in "Science" in 2000, led to 3 Nobel Prizes (dates unknown) 2002 Celera Genomics Main Contribution: Entire genome of mice sequenced What: Celera Genomics sequences the entire genome of mice and their research proves to be fruitful since mice share almost exactly the same genes that humans have
How: used the whole genome shotgun method- involves taking the DNA to be cloned and cutting it into fragments using a restriction enzyme. These fragments are cloned into a vector where the DNA is processed and sequenced
Why: The mice's DNA is more compatable with a human's DNA than a fruit fly's DNA, having 700 genes that are also present in humans (which even reside together in almost the same order). Sequencing the mouse's genome would be more helpful in understanding the human genome than the fruit fly's genome
Influence of Society: They sequenced its genome because the mouse has always been used as a model animal, having been used to test color mutations and study mammalian biology, and the number of scientists working with mice also increased due to them realizing that working with the mouse genome was the most efficient way to study gene function and to get animal models for human pathologies.
Awards/Works: None similarities between mouse genome and human genome 1961 François Jacob Main Contribution: developed a theory of genetic regulatory mechanisms, showing how, on a molecular level, certain genes are activated and suppressed. What: studied the mechanisms that transfer genetic information and regulate pathways, which adjust the activity and synthesis of macromolecules in bacterial cells
How: They studied the bacteria E. Coli and saw how it repressed the production of enzymes in lactose metabolism when lactose was unavailable.
Why: This showed that certain kinds of genes called regulator genes control the activity of other genes, either by suppressing them or activating them ( in the E. Coli experiment, it suppressed a gene that controls the signaling of the production of enzymes )
Influence of Society: His injury to his hands, caused by the war in Normandy in August 1955, forbid him to continue his practice as a surgeon and led him to study biology instead. The 1958 analogy revealed by genetic analysis of lysogen led him further to study biological mechanisms
Awards/Works: Nobel Prize in Physiology or Medicine 1965, Charles Léopold Mayer prize by the Académie des Sciences (1962) Lactose metabolism in E. Coli Significance of their work... Charles Darwin...Back then, many people believed that the world was created in 7 days and by a intelligent designer. Darwin's findings suggested otherwise, showing that species have lived, grown, and evolved for hundreds of thousands of years. His work laid the foundation for the Theory of Evolution and would change the way people thought about the creation of earth and its inhabitants.
Mendel... Mendel's extensive research and experiments on pea plants would formalize into the Mendelian Laws of Inheritance which would lead others into investigating chromosomes and how certain traits are inherited, creating the field of genetics.
Watson, Crick, and Wilkins....Their model of DNA exposed it as the chemical substance of genes, not proteins which was widely believed to be the molecule that contained genes. It also exposed its ability to self-replicate and recombine during reproduction
Linus Pauling...enabled scientists to understand the link between chemical substances and the structure it composes through his study on amino acids and small peptides, which led to an important discovery, chemical bonds
Thomas Morgan...expanding upon Mendel's work, he established the Chromosomal Theory of Heredity which refined the Mendelian laws and provided evidence between the synthesis of genetics and the evolutionary theory
Frederick Griffith...his work enables others to see that DNA was the molecule of inheritance
Avery, McCarty, Macleod...showed that DNA was the chemical basis for specific, heritable transformations and proved that DNA were not proteins Significance of their work continued... Hershey and Chase...helped to establish that heredity was carried by DNA
Rosalind Franklin...found the double-helix structure of DNA through her X-ray diffractions which would later influence Crick and Watson's model of DNA
Erwin Chargaff...determined the essential components that made up the chemical structure of DNA
Meselson and Stahl...found out how DNA replicates and how it becomes a double helix
Archibald Garrod...found the link between genetic defects and inherited diseases, in which these genetic defects cause inherited diseases. His discovery of "inborn errors of metabolism" led to the idea that normal and abnormal characteristics are determined by genetics
Beadle and the functions of genes in relation to metabolic processes and how they regulate them by directing the synthesis of enzymes, shows that genes aren't just governing hereditary characteristics but also governs functions in the body
Marshall Nirenberg...cracks the genetic code, uncovering the language of DNA and how their inscriptions correlate to twenty amino acids which make up proteins
J. Craig Venter...sped up the process in discovering genes and their functions through his EST method, or Expressed Sequence tags, which were more accurate, faster, and would later lead to automated sequencing
Michael Gottesman...found how DNA replicate in bacteria, showing that drug resistant genes can move from one bacteria to another. His work with cAMP proteins led to his discovery of DNA transfers in somatic cells while working with them to demonstrate growth regulation
Francis. S Collins...contributed to finding disease genes, finding those responsible for cystic fibrosis, Huntington's disease and endocrine cancer syndrome Tatum...reveals Building On Other Scientists... Darwin: Introduces that species have different traits Mendel: establishes Laws of Inheritance based on the dominant and recessive traits seen in his pea plant experiment, expands Darwin's theory, showing how traits are transmitted from one generation to the next Sutton: Pointed out the connections between cytology and Mendelism, closing the gap between cell form and structure and heredity Garrod: his study of alkaptonuria followed the pattern of recessive inheritance described by Gregor Mendel in his experiments with peas.
Stevens and Morgan: Nettie Stevens (developed sex determination of chromosomes) helped Morgan interpret his genetic results from Drosophilia to come up with the Theory of Sex-linked Inheritance
Frederick Griffith- Helped point out that DNA was the molecule of inheritance, further expanding and refining the ideas surrounding inheritance that Mendel discovered
Beadle and Tatum: Worked with Morgan on Drosophilia and expanded his hypothesis that there is a link between genes and their chemical products. Developed ideas from Garrod, that genes produce enzymes, by providing further evidence in their experiments with Neurospora
Avery, Macleod, and McCarty: Reported that they had purified the transforming principle in Griffith's experiment and that it was DNA Crick and Watson: Used Rosalind Franklin's findings on the double-helix structure of DNA with Chargaff's base pairs to construct their double-helix DNA model that was held together by base pairs
Hershey and Chase: 7 years after Avery and his team's discovery that DNA was the gene carrier, they provide the final proof that DNA is the molecule of heredity
Meselson and Stahl: Puzzled by Watson and Crick's model, which suggested that the two strands of the double helix dissociated and created a new complementary strand, they experimented and observed that the DNA actually replicates semi conservatively
Nirenberg: Used Chargaff's base codes to help crack the genetic code, this would have been impossible if DNA was not first discovered to be the genetic carrier and its structure was not identified ( which was founded by Avery, Macleod, McCarty, Crick and Watson, and Rosalind )
Fred Sanger: Sanger's Shotgun method uses Chargaff's base pairs to help sequence DNA by using chemical reagents to split the DNA strand along its bases
Venter: Discovered the EST method which uses the sequence of bases transcribed in mRNA, founded by Nirenberg, to produce complementary DNA
Celera Genomics: Uses Sanger's shotgun method to sequence entire genomes like the Fruit Fly's and the mice's Building On Other Scientists Continued... Sources: "Genome News Network - Home." Genome News Network - Home. N.p., n.d. Web. 06 Jan. 2013.
"History of Genetics Timeline." History of Genetics Timeline. N.p., n.d. Web. 06 Jan. 2013.
"The Nobel Prizes." The Nobel Prizes. N.p., n.d. Web. 06 Jan. 2013.
"Hershey and Chase Experiment." Hershey and Chase Experiment. N.p., n.d. Web. 06 Jan. 2013.
BBC News. BBC, n.d. Web. 06 Jan. 2013.
PBS. PBS, n.d. Web. 06 Jan. 2013.
"Erwin Chargaff." â Biography. N.p., n.d. Web. 06 Jan. 2013.
"NNDB: Tracking the Entire World." NNDB: Tracking the Entire World. N.p., n.d. Web. 06 Jan. 2013.